Geomagnetic Storms:Probabilities for significant disturbances in Earth's magnetic field are given for three activity levels: active, minor storm, severe storm

Updated at: 2016 Aug 24 2200 UTC

Mid-latitudes

0-24 hr

24-48 hr

ACTIVE

15 %

10 %

MINOR

05 %

05 %

SEVERE

01 %

01 %

High latitudes

0-24 hr

24-48 hr

ACTIVE

15 %

15 %

MINOR

20 %

20 %

SEVERE

15 %

15 %

Wednesday, Aug. 24, 2016

What's up in space

Directly under the Arctic Circle! Marianne's Arctic Xpress in Tromsø offers fjord, whale and wildlife tours by day, aurora tours by night. Book Now and get a 10% discount on combo day and night adventures.

A HEAVENLY ALIGNMENT: When the sun goes down tonight, step outside and face south. Saturn, Mars and the red giant star Antares have formed a vertical line in the night sky. Golden Saturn is on top, tiger-colored Mars in the middle, and fiery Antares on the bottom. Enjoy the show! [sky map]

AURORAS VS TWILIGHT: A G1-class geomagnetic storm on Aug. 23-24 has sparked late summer auroras around the Arctic Circle, mixing twilight-blue with aurora-green. It's a palette of rare beauty, which you can only see at this time of year. Rauno Pakarinen sends this picture from Lake Pieksäjärvi, Finland:

"The auroras started to glow during twilight and I continued watching them for hours until the clouds started rolling in later in the night," says Pakarinen. "It was our first real auroral display of early autumn."

The storm was ignited by the unexpected arrival of a fast-moving solar wind stream. NOAA forecasters estimate a 20% chance of additional storms on Aug. 24th as the solar wind continues to buffet Earth's magnetic field. The odds of a light show may be even higher as a result of the stream's aurora-friendly magnetization. Aurora alerts: text or voice

SPACE WEATHER BALLOON OVER THE ANDES: Spaceweather.com and the students of Earth to Sky Calculus have just released four space weather balloons in less than three days--from Chile, California, Oregon, and Washington. The rapid-fire launches are in support of the Intercontinental Space Weather Balloon Network, which spans 3 countries, two continents, and more than 10,000 miles. A highlight so far is the Chilean launch of Aug 20th. That balloon reached an altitude of 37.4 km (122,700 feet), a record for our 5 year-old ballooning program. Here is the space weather payload soaring over the Andes:

The purpose of our (exhausting) activity is two-fold:

First, it's a giant experiment in atmospheric radiation. Our payloads contain radiation sensors that allow us to measure cosmic rays from deep space. We will find out how this penetrating form of radiation varies around the Americas at altitudes ranging from ground level to the stratosphere. The results will be especially interesting in Chile, where the balloon ascended into the outskirts of the South Atlantic Anomaly, a high radiation zone caused by a weakness in Earth's magnetic field.

Second, we're practicing for Aug. 21, 2017--the date of the Great American Solar Eclipse. One year from now, we will launch more than a dozen balloons into the path of totality to photograph the eclipse from the stratosphere and create a unique movie of the Moon's shadow sweeping across North America. Such an ambitious project requires practice, and we're starting now.

NASA REGAINS CONTACT WITH LOST SPACECRAFT: In a surprising development, NASA has regained contact with the STEREO-B spacecraft after two years of silence. STEREO-B, which can see the farside of the sun, went quiet in 2014 after mission controllers tested a communications reset procedure. Unfortunately, STEREO-B failed the test. Since then, NASA has regularly attempted to regain contact using the Deep Space Network. On Aug. 21st, they succeeded, managing to receive a downlink carrier for several hours. In the days and weeks ahead, engineers will take steps to assess the health of STEREO-B and return it to service. Solar flare alerts: text or voice

Every night, a network of NASA all-sky cameras scans the skies above the United States for meteoritic fireballs. Automated software maintained by NASA's Meteoroid Environment Office calculates their orbits, velocity, penetration depth in Earth's atmosphere and many other characteristics. Daily results are presented here on Spaceweather.com.

In this diagram of the inner solar system, all of the fireball orbits intersect at a single point--Earth. The orbits are color-coded by velocity, from slow (red) to fast (blue). [Larger image] [movies]

Near Earth Asteroids

Potentially Hazardous Asteroids (PHAs) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones all the time.

These measurements are based on regular space weather balloon flights: learn more.

Approximately once a week, Spaceweather.com and the students of Earth to Sky Calculus fly "space weather balloons" to the stratosphere over California. These balloons are equipped with radiation sensors that detect cosmic rays, a surprisingly "down to Earth" form of space weather. Cosmic rays can seed clouds, trigger lightning, and penetrate commercial airplanes. Our measurements show that someone flying back and forth across the continental USA, just once, can absorb as much ionizing radiation as 2 to 5 dental X-rays. For example, here is the data from a flight on Oct. 22, 2015:

Radiation levels peak at the entrance to the stratosphere in a broad region called the "Pfotzer Maximum." This peak is named after physicist George Pfotzer who discovered it using balloons and Geiger tubes in the 1930s. Radiation levels there are more than 80x sea level.

Note that the bottom of the Pfotzer Maximim is near 55,000 ft. This means that some high-flying aircraft are not far from the zone of maximum radiation. Indeed, according to the Oct 22th measurements, a plane flying at 45,000 feet is exposed to 2.79 uSv/hr. At that rate, a passenger would absorb about one dental X-ray's worth of radiation in about 5 hours.